1. Field of the Invention
The present invention relates to an electrical connector, and particularly to an electrical connector for a flexible flat cable having a top wall of a shield retained in reliable contact with a housing thereof.
2. Description of the Prior Art
As shown in FIGS. 4 and 5, an earlier invented electrical connector for a flexible flat cable 5, i.e. an FPC (Flexible Printed Circuit) connector, includes a dielectric housing 1 with a plurality of terminals 2 received therein. The housing 1 has an elongate slot 13 for receiving the flexible flat cable 5. A shield 3 encloses the housing 1 for EMI/RFI shielding. The shield 3 comprises a top wall 31, a bottom wall 32 opposite the top wall 31, a pair of opposite lateral walls 35, and a pressing plate 34 extending into a cavity defined between the top wall 31, the bottom wall 32 and the lateral walls 35. The top wall 31 further comprises a fixing plate 311 forwardly extending therefrom at a lower level for fitting into a shallow recess 16 defined in an upper surface 17 of the housing 1. The top wall 31 is connected with the bottom wall 32 via a pair of interconnecting portions 36 proximate the lateral walls 35. The pressing plate 34 is connected with the bottom wall 32 via a pair of rectangular linkers 33. Each linker 33 connects with the pressing plate 34 and the bottom wall 32 at first and second junction portions A and B, respectively.
A stuffer 4 is inserted between the pressing plate 34 and the bottom wall 32 of the shield 3 and is movable between a first, loading position and a final, terminating position. In the first, loading position, the flexible cable 5 is readily inserted into a space defined between the terminals 2 and the pressing plate 34 of the shield 3. In the final, terminating position, the stuffer 4 is further pushed inward to bias signal conductors 52 of the cable 5 into contact with the terminals 2 by an elongate flange 42 formed at a rear edge thereof.
One problem with such a design is that the top wall 311 of the shield 3 tends to deflect relative to the housing 1 during the forward push of the stuffer 4 to the final, terminating position. During this process, an upward force exerted by the stuffer 4 is acting on the pressing plate 34 whereby the shield 3 rotates anticlockwise (with reference to the view in FIG. 5) relative to the housing 1. Since the first junction portion A of the linker 33 has the same width as the second junction portion B, the bottom wall 32 is easily actuated to move upward by the linker 33. Such an upward movement of the bottom wall 32 results in an upward deflection of the top wall 31 relative to the housing 1 via the interconnecting portions 36. Such an upward deflection of the top wall 31 exceeds the preloading stress of the top wall 31. Thus, a significant gap G is defined between the free end of the fixing plate 311 of the shield 3 and the bottom of the recess 16 of the housing 1. When the width of the rectangular linker 33 is 2 mm, the amount of upward deflection of the top wall 31 reaches 0.21 mm. However, due to the miniaturization of the electrical connectors, the height of an FPC connector is generally only about 2 mm and the thickness of a pressing plate of a shield is only about 0.2 mm. Therefore, such a significant gap G is out of line with the miniaturization trend and is thus unacceptable in the art. Furthermore, such a significant gap G degrades the shielding efficiency of the shield 3 and thus adversely affects the electrical connection between the terminals 2 and corresponding complementary terminals.
Therefore, an electrical connector for a flexible flat cable solving the aforesaid problems is desired.